Maintain insurance is essentially pointless (6)
I believe the answer is:
insist
'maintain' is the definition.
(thesaurus)
'insurance is essentially pointless' is the wordplay.
'insurance' becomes 'ins' (business abbreviation).
'essentially' indicates the central letters.
The middle of 'pointless' is 't'.
'ins'+'is'+'t'='INSIST'
(Other definitions for insist that I've seen before include "Take a firm stand" , "Urge" , "Be firm in demands" , "Put one's foot down" , "Be adamant" .)